1. Field of the Invention
The present invention relates to a cable connection structure in which a cable is connected to a board, and a cable connection board.
2. Description of the Related Art
Conventionally, a medical endoscope enables an observation of a lesion site when an insertion unit is deeply inserted to an inside of a body and further enables an examination and a medical treatment in the inside of the body by using a treatment tool together depending on a necessity. As such an endoscope, there is an endoscope provided with an imaging device in which an imaging element such as a CCD is embedded at a distal end of the insertion unit. The endoscope is configured by embedding an imaging module on which an imaging device is mounted in the distal end part of the elongated insertion unit having flexibility and enables an observation and the like of a test site when the insertion unit is inserted in an inside of a body cavity. The distal end part of the insertion unit has been desired to be thinner, shorter, and smaller to ease a pain of a patient.
As a technique for solving the problem, a technique for challenging an improvement in density of signal cables by folding a flexible board connected to an imaging device in half and the like are disclosed in Japanese Patent Application Laid-Open No. H04-197334, for example.
Besides, an electronic endoscope provided with a signal wire fixation groove which fixes a signal wire of a cable on a circuit board in the vicinity of a signal wire connection terminal part is disclosed in Japanese Patent Application Laid-Open No. 2006-14906, for example.
However, it is only possible in the technique disclosed in Japanese Patent Application Laid-Open No. H04-197334 to connect core wires at the same alignment pitch as signal cables on the flexible board. The alignment pitch of cables is generally a pitch aligned by a jig or a pitch aligned at a state where cables are in contact with each other by their outer coverings, and cables are fixed at the aligned state by a lamination and the like, for example. On this occasion, it is at least impossible to connect core wires at a pitch not more than the outermost diameter of the cable. Therefore, there is a restriction of a layout in mounting on a board.
Besides, it is only possible in the technique disclosed in Japanese Patent Application Laid-Open No. 2006-14906 to connect cables at a pitch aligned by their outer covering parts while there is an advantage of being able to prevent a misalignment of signal wires. Moreover, it is difficult to make a dimension small since a circuit board is connected to an imaging device via a wire lead and the like.